Quoth leon...@leonerd.org.uk (Paul LeoNerd Evans): > -=-=-=-=-=- > > On Wed, Apr 22, 2009 at 02:10:03AM +0100, Ben Morrow wrote: > > What am I missing here? It appears to me unpacking "." gives the current > > byte position in the string, which is what is needed. > > > > ~% perl -E'my $bin = pack "NN", 10, 12; say for unpack ".N.N.", $bin' > > 0 > > 10 > > 4 > > 12 > > 8 > > Ah, youknow, that is exactly what I wanted :) > > I had in fact looked up and down the docs for a format which would do > something like that, and didn't find it. Is that documented anywhere? > > I've just sat and reread perldoc -f pack and perldoc -f unpack _again_ > and still haven't spotted it.
It appears (see Peter's reply) that it is only implemented in 5.10. 5.10's perldoc -f pack includes . Null fill or truncate to absolute position specified by value. which (besides being rather terse) doesn't explicitly say that unpack "." will do what it does. Ben